Mercury (Hg) is an important and persistent environmental pollutant that is bioaccumulative and toxic in even small amounts. There are many stable Hg species, with different species exhibiting different characteristics including toxicity, solubility, mobility and bioavailability. Organic Hg and in particular methylmercury ([CH3Hg]+; MeHg) is one of the most toxic Hg species affecting human and animal health. Hg can be found naturally in the environment as well as a result of anthropogenic activities such as mining, Hg manufacture and disposal, and fossil fuel combustion.
Hg contamination has become a global concern as it is often released into the atmosphere in one location with impact on ecosystems in another location, which can be thousands of kilometers away. When Hg enters in an aqueous system, it is subject to methylation, forming MeHg, and demethylation, forming inorganic Hg (InHg), primarily ionic Hg2+ and labile complexes such as HgCl20. Once in the biosystem, MeHg partitions into periphyton, plankton and biota that are eaten by invertebrates and fish. As a result, MeHg bio-magnifies as it accumulates throughout and up the food chain.
Due to both the toxicity as well as the bio-magnification in the food chain, monitoring both total Hg and Hg species is of high importance to assess potential impacts on human and animal health as well as the environment; additionally, understanding spatial and seasonal variability and lability of Hg species in the environment is important to refine the technically based assessment of risks.
What are needed in the art are methods and devices that can provide simple and affordable protocols for Hg monitoring and risk assessment. More specifically, what is needed is a device that can effectively provide information with regard to the presence and/or quantity of particular Hg species in an environment so as to better assess risk. Moreover, methods and devices that differentiate organic Hg from inorganic and elemental Hg and which can function as surrogates for aquatic organisms by simply and accurately determining the presence and/or concentration of specific Hg species that are bioavailable to aquatic organisms could be of great benefit.